Oil-retaining structure on fan rotor

ABSTRACT

An oil-retaining structure on fan rotor includes a rotor body, a rotor shaft, and an oil-retaining portion. The rotor body has an open end and a closed end, on an inner side of which the oil-retaining portion is formed. The oil-retaining portion includes an annular recess, which has an oil-retaining edge and an oil-retaining surface extended between the oil-retaining edge and a bottom of the annular recess. The rotor shaft has a first end connected to the oil-retaining portion and a second end extended through a bearing of a fan. Since the oil-retaining portion is coated with a layer of oil-repellant agent, lubricant oil being centrifugally pulled out of the bearing when the fan operates and caught by the annular recess can quickly flow back to the bearing without remaining in the annular recess due to a capillary action. Therefore, the fan can have increased service life and upgraded operating efficiency.

FIELD OF THE INVENTION

The present invention relates to an oil-retaining structure on a fan rotor, and more particularly to an oil-retaining structure that is formed on a fan rotor and coated with a layer of oil-repellant agent for the retained oil to quickly flow back to the fan bearing.

BACKGROUND OF THE INVENTION

Conventionally, a fan is an assembly of a seat, a wear-resistant strip, a fastening member, a bearing, a rotor shaft, and a rotor. To increase the service life of the fan and to reduce the noise and friction produced during the operation of the fan, the rotor shaft and the bearing are made of a porous material, so that lubricant oil can be stored in the large number of pores in the rotor shaft and the bearing. When the fan operates and a centrifugal force is produced, the lubricant oil stored in the bearing or the rotor shaft is pulled out due to the centrifugal force and acts to lubricate and accordingly reduce the friction resistance between the bearing and the rotor shaft when the fan rotates.

Taiwan Patent Number M331589 discloses a leak-proof structure for oil-impregnated bearing, which internally includes a seat, a wear-resistant strip, a fastening member, a bearing, a rotor shaft, and a rotor. The seat is provided with an axially forward extended bearing cup, into which the above-mentioned parts are arranged. The rotor is internally provided with an oil-retaining plate. Lubricant oil in the bearing being centrifugally thrown out of the bearing is re-collected by the oil-retaining plate, and the re-collected lubricant oil is guided through holes formed on a bottom of a conic recess to flow back to the bearing. Therefore, the lubricant oil having been centrifugally thrown out of the bearing to an outer surface of the oil-retaining plate can flow back to the bearing cup on the seat again. That is, with the above leak-proof structure for oil-impregnated bearing, the oil-retaining plates retains the centrifugally thrown out lubricant oil and guides the retained lubricant oil to flow back to between the bearing and the rotor shaft. While the oil-retaining plate has a structure capable of retaining the centrifugally thrown out lubricant oil and guiding the retained lubricant oil back to between the bearing and the rotor shaft, the lubricant oil is a relatively viscose and sticky fluid with low fluidity and tends to stay on the outer surface of the oil-retaining plate without quickly flowing back to between the bearing and the rotor shaft to lubricate the same. That is, the conventional leak-proof structure for oil-impregnated bearing has the following disadvantages: (1) having low lubricant-oil flow-back efficiency; and (2) adversely resulting in shortened fan service life.

It is therefore tried by the inventor to develop an oil-retaining structure that enables upgraded lubricant oil flow-back efficiency to ensure increased fan service life.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide an oil-retaining structure on fan rotor, so that lubricant oil retained by the oil-retaining structure during the operation of a fan can efficiently flow back to a bearing of the fan.

To achieve the above and other objects, the oil-retaining structure on fan rotor according to the present invention includes a rotor body, a rotor shaft, and an oil-retaining portion. The rotor body has an open end and a closed end, and the rotor shaft has a first end and a second. The first end of the rotor shaft is connected to the closed end of the rotor body, and the second end of the rotor shaft is extended through a bearing of a fan. The bearing is an oil-impregnated bearing and accordingly contains a proper quantity of lubricant oil. The oil-retaining portion is formed on an inner side of the closed end of the rotor body. The oil-retaining portion includes an annular recess externally located around the first end of the rotor shaft. The annular recess has an oil-retaining edge and an oil-retaining surface extended between the oil-retaining edge and a bottom of the annular recess. Since the oil-retaining portion is coated with a layer of oil-repellant agent, lubricant oil being centrifugally pulled out of the bearing when the fan operates and caught by the annular recess can quickly flow back to the bearing without remaining in the annular recess due to a capillary action. Therefore, the fan can have increased service life and upgraded operating efficiency. Further, since the oil-retaining portion is integrally formed on the closed end of the rotor body, the rotor of the fan can be manufactured at reduced cost and upgraded production efficiency.

In brief, the present invention provides the following advantages: (1) enabling high lubricant oil flow-back efficiency; (2) reducing fan manufacturing cost; and (3) upgrading fan production efficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein

FIG. 1 is an exploded sectional view showing an oil-retaining structure on fan rotor according to a preferred embodiment of the present invention and other fan components related thereto;

FIG. 2 is an assembled view of FIG. 1;

FIG. 3 is similar to FIG. 2 showing the oil-retaining structure on fan rotor in use; and

FIG. 3A is an enlarged view of the circled area 3A in FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1 and 2 that are exploded and assembled sectional views, respectively, of an oil-retaining structure on fan rotor according to a preferred embodiment of the present invention. For the purpose of conciseness, the present invention will also be briefly referred to as the oil-retaining structure and generally denoted by reference numeral 1. As shown, the oil-retaining structure 1 includes a rotor body 11, a rotor shaft 12, and an oil-retaining portion 13. The rotor body 11 has an open end 111 and a closed end 112. The oil-retaining portion 13 is formed on an inner side of the closed end 112, and includes an annular recess 131. The annular recess 131 has an oil-retaining edge 1311 and an oil-retaining surface 1312. The oil-retaining surface 1312 is extended between a bottom of the annular recess 131 and the oil-retaining edge 1311. The rotor shaft 12 has a first end 121 and a second end 122. The first end 121 of the rotor shaft 12 is forward inserted into a central area of the oil-retaining portion 13 on the closed end 112 of the rotor body 11, and the second end 122 of the rotor shaft 12 is rearward extended through and accordingly, associated with a bearing 21 of a fan 2. The bearing 21 is an oil-impregnated bearing and therefore contains a proper quantity of lubricant oil 4. The oil-retaining portion 13 is coated with a layer of oil-repellent agent 3. With the layer of oil-repellent agent 3 coated on the oil-retaining portion 13, the lubricant oil 4 being centrifugally pulled out from the bearing 21 and caught by the oil-retaining portion 13 will not remain in the oil-retaining portion 13 due to a capillary action. Instead, the retained lubricant oil 4 will quickly flow back to a bearing cup 221, in which the bearing 21 is received.

The rotor body 11 is externally provided with a plurality of fan blades 113. The oil-retaining portion 13, the rotor body 11, and the rotor shaft 12 are concentric with one another. The rotor body 11 is further provided on the inner side of the closed end 112 with an axially rearward extended shaft receiving portion 114. The annular recess 131 of the oil-retaining portion 13 is externally located around the shaft receiving portion 114, and the shaft receiving portion 114 has a height smaller than that of the oil-retaining edge 1311. More specifically speaking, the first end 121 of the rotor shaft 12 is forward inserted into the shaft receiving portion 114.

Please refer to FIGS. 1, 3 and 3A at the same time. As shown, the oil-retaining structure 1 is applied to a fan 2. The fan 2 includes a bearing seat 22 and at least one bearing 21. The bearing seat 22 includes an axially forward extended bearing cup 221, in which the bearing 21 is received. The bearing 21 has a shaft hole 211. The second end 122 of the rotor shaft 12 is extended through the shaft hole 211 of the bearing 21, and the lubricant oil 4 also exists between the rotor shaft 12 and the shaft hole 211. When the fan 2 operates, the rotor shaft 12 brings the rotor body 11 to rotate at the same time. And, when the rotor shaft 12 rotates, a centrifugal force is produced to pull the lubricant oil 4 in an axial or a radial direction of the rotor shaft 12. The lubricant oil 4 being centrifugally pulled in the axial direction of the rotor shaft 12 is caught by and collected in the annular recess 131 of the oil-retaining portion 13, and then guided by the oil-retaining surface 1312 to the oil-retaining edge 1311, from where the lubricant oil 4 is guided into the bearing cup 221.

The oil-retaining portion 13 of the oil-retaining structure on fan rotor 1 is able to catch the lubricant oil 4 that is centrifugally pulled out of the bearing 21. With the oil-retain portion coated with a layer of oil-repellant agent 3, the lubricant oil 4 will not remain in the oil-retaining portion 13 due to a capillary action. Instead, the retained lubricant oil 4 will quickly flow back into the bearing cup 221. Therefore, with the above arrangements, the fan 2 can have increased service life and further enhanced operating efficiency. Moreover, since the oil-retaining portion 13 is integrally formed on the inner side of the closed side 112 of the rotor body 11, the fan 2 can have simplified structure to reduce the manufacturing cost and upgrade the assembling efficiency thereof.

The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims. 

1. An oil-retaining structure on fan rotor, comprising: a rotor body having an open end and a closed end; a rotor shaft having a first end and a second end, and the first end being connected to an inner side of the closed end of the rotor body; and an oil-retaining portion being formed on the inner side of the closed end of the rotor body, and including an annular recess externally located around and spaced from the first end of the rotor shaft; the annular recess having an oil-retaining edge and an oil-retaining surface, the oil-retaining surface being extended between a bottom of the annular recess and the oil-retaining edge, and the oil-retaining portion being coated with an oil-repellant agent.
 2. The oil-retaining structure on fan rotor as claimed in claim 1, wherein the rotor body is externally provided with a plurality of fan blades.
 3. The oil-retaining structure on fan rotor as claimed in claim 1, wherein the oil-retaining portion, the rotor body and the rotor shaft are concentric with one another.
 4. The oil-retaining structure on fan rotor as claimed in claim 1, wherein the rotor body is further provided on the inner side of the closed end with an axially rearward extended shaft receiving portion, into which the first end of the rotor shaft is inserted; and the shaft receiving portion having a height smaller than that of the oil-retaining edge of the annular recess of the oil-retaining portion. 